| Autor: |
Senthilkumar S; Inorganic Materials & Catalysis Division, CSIR-Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar-364 002, Gujarat, India. sneogi@csmcri.res.in., Maru MS, Somani RS, Bajaj HC, Neogi S |
| Jazyk: |
angličtina |
| Zdroj: |
Dalton transactions (Cambridge, England : 2003) [Dalton Trans] 2018 Jan 02; Vol. 47 (2), pp. 418-428. |
| DOI: |
10.1039/c7dt03754f |
| Abstrakt: |
Amine-functionalised framework NH 2 -MIL-101(Al) was synthesized using a solvothermal and microwave method and characterized by PXRD, FT-IR, TGA, SEM-EDX, and BET surface area analysis. The desolvated framework, in the presence of co-catalyst tetrabutylammonium bromide (TBAB), acted as an excellent heterogeneous catalyst for the solvent-free cycloaddition of carbon dioxide (CO 2 ) with epoxides, affording five-membered cyclic carbonates. Using styrene oxide, the NH 2 -MIL-101(Al)/TBAB system showed more than 99% conversion, affording 96% yield and 99% selectivity with a turn over frequency of 23.5 h -1 . This validated the synergistic effect of the quaternary ammonium salt during CO 2 cycloaddition. The catalyst could be recycled at least five times without a noticeable loss in activity, while leaching test showed no leached Al 3+ ions throughout the reaction. Thorough analysis of the reaction parameters showed that the optimum conditions for obtaining the maximum yield and highest selectivity were 120 °C and 18 bar of CO 2 for 6 h. The outstanding conversion and selectivity were maintained for a range of aliphatic and aromatic epoxides, corroborating the duel benefit of the micro-mesoporous system with amine functionality, which offered easy access for reactant molecules with diverse sizes, and provided inspiration for future CO 2 cycloaddition catalytic systems. We also propose a rationalized mechanism for the cycloaddition reaction mediated by NH 2 -MIL-101(Al) and TBAB based on literature precedent and experimental outcome. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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